Double-pole rotary converter.



1. L. LA coum v D OUBLE POLE ROTARY CONVERTER. APPLICATION FILED APR.23. 1914.

Patented Apr. 23, 1918.

2 SHEETS-SHEET I.

1. L. LA COUR.

DOUBLE POLE ROTARY CONVERTER.

APPLICATION HLED APR-23. 1914.

Patented Apr. 23, 1918.

2 SHEETS-SHEET 2.

JENS LASSEN LA coon, or VESTERAS, SWEDEN.

DOUBLE-?OLE ROTARY CONVERTER.

Specification of Letters Patent.

Patented Apr. 23, 1918.

Application filed April 23, 1914. Serial No. 833,887.

To all whom it may concern:

Be it known that I, J ENS LASSEN LA Conn, a citizen of the Kingdom ofSweden, residing at Vesteras, Sweden, have invented new and usefulImprovements in Double-Pole Rotary Converters, of which the following isa specification.

This invention relates to improvements in dynamo electric machinery inwhich an alternating current machine and a direct current machine are soincorporated into one machine as to provide what may be termed a doublepole converter also applicable for use as a double current machine; themachine, which has two different kinds of fields having differentnumbers of poles, is mainly for use as a converter, but may be used togenerate two different kinds of current. The direct current voltage ofthe machine is quite independent of the alternating current voltage, andis adapted to be regulated at will. The windings of the respectivemachines are, as stated, carried out with difierent numbers of poles andthese numbers usually have a ratio of one to two. Obviously the machinemay be used as a motor supplied with both alternating and directcurrent.

The alternating current machine may be of the asynchronous type or theauto-synchronous type; the term auto-synchronous is used to denote anasynchronous induction motor the secondary winding of which, after themotor has been started up as an induction motor, is adapted to beexcited by direct current, thus changing the motor into a synchronousmotor; in either case the alternating current machine is constructed asan ordinary induction motor and started up as such, but after reachingsynchronous speed the secondary winding (except when carried out as asquirrel-cage winding) is excited with direct current, and the motorruns as a synchronous machine.

The primary winding of the alternating current machine is arranged onthe rotor and the secondary winding on the stator, so that the latter isplaced in the pole faces of the direct current machine; the fieldwinding of the direct current machine and the secondary winding of thealternating current machine are well adapted for arrangement on the samestator core, the secondary Winding being carried out in a single windingover the pole face either as a uniformly distributed coil or barwinding, winding being carried out with a single coil per pole, afterthe manner of the field winding of a direct current machine with salientpoles.

The machine can be started in the ordinary way as an induction motorwith resistance in the secondary circuit, which in this case is arrangedon the stator. After having been started the machine can, as stated, beconverted into a synchronous machine and run as such by leading directcurrent into the secondary winding. The secondary winding may also becarried out as a squirrel-cage winding, in which case the machine may bestarted in any well known manner, for example, by means of anautostarter or the like.

The machine may also be started from the direct current side, or bymeans of a special starting motor. lVhen the alternating current machineis a single phase machine, it may be started from the alternatingcurrent side by means of an auxiliary primary winding constituting asplit phase arrangement.

All these features are well known features of double pole converters,but such known machines have generally twice as many poles on the A. C.side as on the D. C. side, while the present invention has in viewspecial improvements in double pole converters in which there may betwice as many poles on the D. C. side as on the A. C. side.

The first improvement is to combine the secondary winding of the A. C.machine with the compensating winding of the D. C. machine in order toget the simplestand most suitable winding arrangement on the stator, thesmallest copper weight and the smallest copper losses.

In the accompanying drawing some constructional forms of the inventionare illustrated diagrammatically.

Figure 1 shows an asynchronous converter provided with two windings onthe stator, one of which is a continuous current field winding while theother is a secondary winding of the asynchronous machine and and thefield at the same time a compensating or commutating pole winding of thecontinuous current machine.

Fig. 2 shows a single-phase auto-synchronous converter.

Fig. 3 shows a modified form of the converter shown in Fig. 2. p

Fig. t shows another form of a threephase asynchronous converter.

Fig. 5 shows another form of an autosynchronous converter.

Fig. 6 shows the essential features of a machine constructed accordingto the present invention.

Fig. 1 shows an asynchronous converter provided with two alternatingcurrent poles and four poles on the continuous current part. The rotoris provided, on the one hand, with a three-phase bi-polar alternatingcurrent winding All connected by means of sliprings s s and brushes Z2,6 2),, with the terminals 1, II, III, of the three-phase circuit, and,on the other hand, with a four-pole continuous current armature windingAL connected through a commutator and brushes B B and B B, with theterminals L L respectively of a continuous current circuit. K, Kindicate compensating or commutating pole-windings for the continuouscurrent portion of the machine, said windings being placed on thestator.

The secondary winding FWV of the alter nating current portion placed onthe stator may be connected as a bi-polar winding and may beshort-circuited along two axes ca -a and (L -a, at right angles to oneanother, as is shown on the drawing for the sake of simplicity, or maybe provided with a starting resistance in the well-known manner, inorder to facilitate the starting. Said secondary winding serves, at thesame time, as a four polar compensating winding for the continuouscurrent portion. For this purpose the winding FlV is at the points a,and a, connected in series with the continuous current portion of theconverter. FL designates a four-polar field-winding for the continuouscurrent portion of the machine placed on the stator and being fed fromthe eXciter M which has a shunt field winding FM provided with aregulating re sistance VM.

The continuous current machine is provided with a number of polesdiflering from that of the alternating current machine, in order thatboth machines shall be capable of working independently of one another.If, as in Fig. 1, the alternating current machine is bi-polar, thecontinuous current machine may suitably be four-polar; and if thealternating current machine is fourpolar, the continuous current machinemay suitably be bi-polar, and so on. The proportion between the numbersof poles of both machines may suitably be 1:2 or 2 l, the invention is,however, not limited to said relations. Therefore, each machine worksindependently of the other one, though provided with common statorandrotor-cores, and the Voltage of the continuous current may be controlledat will, as for instance by regulating the strengtlrof field of thecontinuous current machine. For this purpose a regulating resistance maybe used in the circuit of the field winding.

In 1 the direct current winding of the rotor is shown diagrannnaticallyit may be an ordinary winding, rin or drum, but if so the arrangon'ientof the four brushes shown cannot be employed, and two only would beused. It is, however, easy to so arrange the winding All that the fourbrush arrangement illustrated can be adopted, and to do this each coil.which can be shortcircuited, is so wound as to comprise four barsarranged in series, which bars are under the four direct current polesand accordingly under the two alternating current poles. A suitable lapwinding and a suitable wave winding may be used, which differs from anordinary winding by the omission of every second commutator bar, andobviously the same result can be ohtained with an ordinary winding ifhalt the brushes be omitted.

In Fig. 2 ATV designates a single phase, bi-polar alternating currentwinding placed on the rotor and, by means of slip-rings s, s, andbrushes b, I), connected with the terminals I, ll of a single phasealterimtlng current circuit. AL is connected as a fourpolar continuouscurrent ari'nature winding also placed on the rotor and by a commutatorand brushes B, B, and B 1 connected with terminals L L of a continuouscurrent circuit.

K, K designate (amimutating pole windings placed on the stator andconnected in series with the continuous current armature circuit. FV maybe connected as a bi-polar secondary winding placed on the stator andfed with continuous current from the excil'er M when said machine runsas an autosyncln'onous machine. The same winding is also used as acompensating winding for the four polar continuous current armaturewinding, and for this purpose the armature current is supplied at thepoints H and, H The point H is the zero point of a balancing transformerconnected in the usual manner with the exciter M. The large arrows referto the exciting current of the alternating current machine, and thesmall arrows to the compensating current of the continuous currentmachine. The former current may be regulated by regulating the 'oltageof the emitter or by simultaneous and equal regulation of theresistances Pill", and RlV The secondary winding FV is directlyshort-circuited between the points a, and a and, by the armature of theenciter M, between the points a and 61,. FL indicates a four-polarcontinuous current field winding for the continuous current portion ofthe converter, and the said winding is fed from the eXciter M.

In the machine shown in Fig. 3 the rotor windings A W and AL and thecommutating pole windings K K are arranged in the same manner as in Fig.2. The stator is likewise provided, on the one hand, with a secondarywinding FW serving at the same time as a compensating winding for thecontinuous current portion of the converter, and on the other hand witha fourpolar continuous current field-winding FL. The connection dilfersfrom that shown in Fig. 2 only in that the compensating current passes,on the one hand, directly from a, to the terminal L and, on the otherhand, from a through the armature of the motor and the regulatingresistance KW, to the terminal L,.

In the machine shown in Fig. 42 AW is a four-polar three-phase, primarywinding placed on the rotor, and AL is connected as a bi-polar,continuous current armature winding. K is a commutating pole-windingplaced on the stator. FVV is a three-phase secondary winding placed onthe stator and serving at the same time as a compensating winding forthe continuous current portion of converter. FL is a bi-polarfield-winding provided with the regulating resistance Eli and connectedwith the terminals L, and lb, of the continuous circuit. The mode ofoperation will appear from the foregoing description.

The machine shown in Fig. 5 is provided with a rotor of the sameconstruction as that shown in Fig. 4:- The stator is provided with adivided secondary winning FlV which is short-circuited, on the one hand,directly between the points 70, 71: and 7c, is, and, on the other hand,through the armature of the eXciter between the points 70 79 The windingFVV serves at the same time as compensating winding for the continuouscurrent portion of the converter, and for this purpose the aid windingis connected in series with the continuous current circuit of theconverter, substantially in the same manner. s is shown in Fig. '2. FLis a bi-polar continuous current field-winding placed on the stator andfed from the eX- citer M. After starting, the converter is brought tosynchronism by means of continuous current supplied to the secondarywinding FlV at the points is, 70

The sectional view shown in Fig. 6 of a machine constructed according tothe present invention will be easy to understand by the aid of thereference characters thereon. A machine according to this invention neednot necessarily be used as a converter for transforming alternatingcurrent to continuous current, but may also be used for convertingcontinuous current into alternating current or as a double currentgenerator for generating simultaneously continuous current andalternating currents.

Although the drawings show converters provided with a single-phase orthree-phase alternating current portion, it is obvious that theinvention is not limited to such a construction, but that thephase-number may be chosen at will.

I claim 1. In a dynamo-electric machine operable as a motor-generator ora double current generator, the combination of an asynchro nousalternating current machine and a continuous current machine havingdifferent numbers of poles and common stator and rotor cores, theprimary winding of the asynchronous machine being disposed on the rotorand the secondary winding being disposed on the stator, the latterwinding being provided with short-circuiting connections correspondingwith the number of poles of the alternating field, and being connectedin series with the armature windings and the leads of the continuouscurrent machine to constitute a compensating winding therefor,substantially as and for the purpose set forth.

:2. In a dynamo-electric machine serving as motor-generator or as doublecurrent generator, the combination of an alternating current machine anda continuous current machine having different numbers of poles andcommon rotor and stator cores, the primary winding of the alternatingmachine being disposed. 011 the rotor and the secondary winding beingdisposed on the stator, the latter winding being provided withshort-circuiting connections corresponding with the number of poles ofthe alternating field, and being connected in series with the armaturewindings and the leads of the continuous current machine to constitute acompensating winding therefor, and means for exciting the latter windingfor synchronous speed, substantially as and for the purpose set forth.

In testimony that I claim the foregoing as my invention, 1 have signedmy name in presence of two subscribing witnesses.

K. E. Wrnnne.

Copies of this patent may lie obtained for five cents each, byaddressing the Commissioner of intents,

Washington, D. G.

